A renewable DNA biosensor for sensitive detection of DNA methyltransferase activity based on cascade signal amplification

摘要

DNA methyltransferase catalyzes the methylation process of DNA. As a potential biomarker, methyltransferase activity assay has attracted more and more attention. Herein, we present a new biosensor based on cascade invasive reactions for DNA methyltransferase activity analysis. The sensing probes on the biosensor were first methylated by the Dam MTase and then cleaved by the Dpnl endonuclease. The cleaved probe acted as upstream probe for the invasion reaction, triggering a highly sensitive signal amplification reaction that produced a strong fluorescent signal. After detection, the cleaved probes were extended by DNA polymerase, and regenerated to be an intact sensor. Meanwhile, as the invasion reaction was a sequence-independent signal amplification method, our proposed biosensor could be a universal strategy for other enzyme activity analysis, simply by replacing the recognition sequence.